1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2018 Emmanuel Vadot <manu@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD$
28 */
29
30#include <sys/types.h>
31#include <sys/ioctl.h>
32#include <stdbool.h>
33#include <sys/capsicum.h>
34#include <dev/pwm/pwmc.h>
35
36#include <err.h>
37#include <errno.h>
38#include <fcntl.h>
39#include <limits.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44#include <capsicum_helpers.h>
45
46#define	PWM_ENABLE	0x0001
47#define	PWM_DISABLE	0x0002
48#define	PWM_SHOW_CONFIG	0x0004
49#define	PWM_PERIOD	0x0008
50#define	PWM_DUTY	0x0010
51
52static char device_name[PATH_MAX] = "/dev/pwm/pwmc0.0";
53
54static void
55set_device_name(const char *name)
56{
57
58	if (name[0] == '/')
59		strlcpy(device_name, name, sizeof(device_name));
60	else
61		snprintf(device_name, sizeof(device_name), "/dev/pwm/%s", name);
62}
63
64static void
65usage(void)
66{
67	fprintf(stderr, "Usage:\n");
68	fprintf(stderr, "\tpwm [-f dev] -C\n");
69	fprintf(stderr, "\tpwm [-f dev] [-D | -E] [-p period] [-d duty[%%]]\n");
70	exit(1);
71}
72
73int
74main(int argc, char *argv[])
75{
76	struct pwm_state state;
77	int fd;
78	u_int period, duty;
79	int action, ch;
80	cap_rights_t right_ioctl;
81	const unsigned long pwm_ioctls[] = {PWMGETSTATE, PWMSETSTATE};
82	char *percent;
83	bool setname;
84
85	action = 0;
86	setname = false;
87	fd = -1;
88	period = duty = -1;
89
90	while ((ch = getopt(argc, argv, "f:EDCp:d:")) != -1) {
91		switch (ch) {
92		case 'E':
93			if (action & (PWM_DISABLE | PWM_SHOW_CONFIG))
94				usage();
95			action |= PWM_ENABLE;
96			break;
97		case 'D':
98			if (action & (PWM_ENABLE | PWM_SHOW_CONFIG))
99				usage();
100			action |= PWM_DISABLE;
101			break;
102		case 'C':
103			if (action)
104				usage();
105			action = PWM_SHOW_CONFIG;
106			break;
107		case 'p':
108			if (action & PWM_SHOW_CONFIG)
109				usage();
110			action |= PWM_PERIOD;
111			period = strtoul(optarg, NULL, 10);
112			break;
113		case 'd':
114			if (action & PWM_SHOW_CONFIG)
115				usage();
116			action |= PWM_DUTY;
117			duty = strtoul(optarg, &percent, 10);
118			if (*percent == '%') {
119				if (duty > 100) {
120					fprintf(stderr,
121					    "Invalid duty percentage\n");
122					usage();
123				}
124			} else if (*percent != '\0')
125				usage();
126			break;
127		case 'f':
128			setname = true;
129			set_device_name(optarg);
130			break;
131		case '?':
132			usage();
133			break;
134		}
135	}
136
137	if (action == 0)
138		usage();
139
140	if ((fd = open(device_name, O_RDWR)) == -1) {
141		fprintf(stderr, "pwm: cannot open %s: %s\n",
142		    device_name, strerror(errno));
143		if (setname)
144			exit(1);
145		else
146			usage();
147	}
148
149	if (caph_limit_stdio() < 0) {
150		fprintf(stderr, "can't limit stdio rights");
151		goto fail;
152	}
153	caph_cache_catpages();
154	cap_rights_init(&right_ioctl, CAP_IOCTL);
155	if (caph_rights_limit(fd, &right_ioctl) < 0) {
156		fprintf(stderr, "cap_right_limit() failed\n");
157		goto fail;
158	}
159	if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
160		fprintf(stderr, "caph_ioctls_limit() failed\n");
161		goto fail;
162	}
163	if (caph_enter() < 0) {
164		fprintf(stderr, "failed to enter capability mode\n");
165		goto fail;
166	}
167
168	/* Fill the common args */
169	if (ioctl(fd, PWMGETSTATE, &state) == -1) {
170		fprintf(stderr, "Cannot get current state of the pwm controller\n");
171		goto fail;
172	}
173
174	if (action == PWM_SHOW_CONFIG) {
175		printf("period: %u\nduty: %u\nenabled:%d\n",
176		    state.period,
177		    state.duty,
178		    state.enable);
179	} else {
180		if (action & PWM_ENABLE)
181			state.enable = true;
182		if (action & PWM_DISABLE)
183			state.enable = false;
184		if (action & PWM_PERIOD)
185			state.period = period;
186		if (action & PWM_DUTY) {
187			if (*percent != '\0')
188				state.duty = (uint64_t)state.period * duty / 100;
189			else
190				state.duty = duty;
191		}
192
193		if (ioctl(fd, PWMSETSTATE, &state) == -1) {
194			fprintf(stderr,
195			  "Cannot configure the pwm controller\n");
196			goto fail;
197		}
198	}
199
200	close(fd);
201	return (0);
202
203fail:
204	close(fd);
205	return (1);
206}
207